1. Field of the Invention
The present invention relates to stop valves attached to sinks and other plumbing fixtures attached to the waste stack, and more specifically, such valves which prevent waste water from backing up into these fixtures.
2. Description Relative to the Prior Art
Most modern plumbing fixtures contain a trap, attached in proximity to the fixture, which prevents gasses, especially sewer gasses, from escaping through the fixture into the atmosphere of the room in which the fixture is located.
Such traps do not, however, prevent liquids under pressure from backing up into the fixture. This is an especial problem in the case of multi-family dwellings, in which the pressure can result from waste water from upper floors which accumulates in a drain or waste stack due to a blockage below. Such a situation is shown in FIG. 1.
Referring now to FIG. 1, the blockage 2, in waste stack 4, will cause water to accumulate up to level 18, which is above the level of sink 10, although not above the level of sinks 6 and 8. The waste stack is the main conduit to conduct waste water from fixtures such as sinks, dishwashers, clothes washers, etc. into the sewer or septic system. Other fixtures, including toilets and urinals, utilize a separate waste stack, and the present invention does not relate to these latter types of fixtures.
Still referring to FIG. 1, the resulting hydrostatic head as a result of the blockage shown will be sufficient to overcome the resistance of P-trap 16, and back up into sink 10, causing it to overflow.
In the case where sinks 6 and 8 are in separate family dwellings within the same house, it may not even be apparent to the residents of the units containing sinks 6 and 8 that a problem exists, as the waste water from these sinks will disappear, but instead of exiting through the sewer pipe in the cellar, the water is all overflowing into the residence containing sink 10.
The present invention remedies this problem by inserting a stop valve between each sink and the waste stack to which it is connected. The stop valve will allow water to flow from the sink toward the waste stack, but will not permit water to flow in the opposite direction. This valve may be likewise used in every plumbing fixture in the house.
A general object of the current invention is to provide a means for preventing backup from a waste stack into plumbing fixtures attached to the stack.
In accordance with one aspect of the invention, a method for installing plumbing fixtures, each having a waste water output, in a multi-floor building having a waste stack, includes inserting a stop valve between the waste water output of each fixture and the waste stack. The stop valve allows the waste water to flow from the fixture toward the waste stack, but prevents flow from the waste stack to the waste output of the fixture.
In accordance with a second aspect of the invention, the valve further is made up of a body, a lower assembly having a water outlet, an upper assembly having an upper seat and a water inlet, and a stop ball within the body. The stop ball has a diameter larger than that of the upper seat, and is restrained from descending onto the lower seat in the absence of water flow. As a result when water flows into the outlet, the stop ball is pressed against the upper seat, preventing the water from flowing into the inlet. However, the waste water is allowed to flow freely from the inlet into the outlet.
In accordance with a third aspect of the invention, the fixtures include one or more sinks, and each sink has a sink strainer at the bottom, and has a P-trap is affixed between the sink strainer and the waste stack. Each stop valve is located between a sink strainer and a corresponding P-valve.
According to a fourth aspect of the invention, a dishwasher producing waste water is located in proximity to one or more of the sinks. The waste water of one or more of the dishwashers is conducted to the stop valve below the stop ball restraints, so that the dishwasher waste water cannot back up into the sink.
In accordance with a fifth aspect of the invention, the valve body is substantially cylindrical.
According to a fifth aspect of the invention, the upper assembly and lower assembly are attached to the body by means of ears located on the upper and lower assemblies which mate with slots on the upper and lower portions of the body. An upper O-ring is affixed to the upper assembly, and a lower O-ring affixed to the lower assembly, thus providing a water-tight seal between the upper assembly and the body, and between the lower assembly and the body.
According to a sixth aspect of the invention, the water inlet of the upper assembly and the water outlet of the lower assemblies are threaded.
According to a seventh aspect of the invention, the upper assembly has internal threads, whereas the lower assembly has external threads.
According to an eighth aspect of the invention, the valve body is symmetrical, and the locations of the upper and lower assemblies may be reversed in their position relative to the body.
According to a ninth aspect of the invention, a T-adapter, having an upper end and a lower end, is attached at the upper end to a strainer thread of a sink, and at the lower end to the threads of the upper assembly. The T-adapter serves as a port for the attachment of an exhaust water exhaust hose from the dishwasher.
According to a tenth aspect of the invention, the valve body contains a port located below the stop-ball restraints, into which the exhaust water of a dishwasher may be conducted by the dishwasher exhaust hose. Thus configured, the dishwasher exhaust water cannot back up into the inlet.
According to an eleventh aspect of the invention, three or more restraint arms are integrally formed in the valve body.
According to a final aspect of the invention, the upper and lower assemblies, and the valve body are molded from plastic.